INTRODUCTION. 
157 
but 13 uttered so inwardly, that it is almost necessary 
to stand beneath the tree upon which the bird is 
perched, before its notes can be heard."* 
In their habits, so far as we are acquainted with 
them, they are active and almost restless. The 
forms of the Old World constantly flit from shrub 
to shrub, and from flower to flower, in search of 
food, which, by nearly all our writers, has been de- 
scribed to be the sweet juices found in the bottom 
of the corolla or in the nectaries, or the sweet sap 
which several trees naturally give out ; at seasons 
only, when these materials were w anting, repairing 
to the search of minute insects ; in searching thus, 
they never employ the hovering flight of the Hum- 
ming-birds, but clamber and suspend themselves by 
the trunks or branches in the manner most conve- 
nient to gain access to the, in many instances, 
lengthened corolla, and in their general activity 
now show a close resemblance to the Titmice, or 
scansorial warblers of America. The form of the 
bill and lengthened tongue are both adapted for be- 
ing plunged into the tubes of flowers ; but another 
structure in the bill induces us to believe that they 
(Nectarinia) are more insectivorous at all times than 
what has been generally considered. We mean the 
minutely and regularly dentated margins of the 
mandibles, so delicate as not to be perceptible with- 
out the aid of a magnifier. Now, we never find 
this structure where some prey is not to be seized 
and held. Among some of the Humming-birds it 
* Gould, Birds of Australia. 
